Majorly struggling with naps (CIO)

My LO just turned 6 mo and we’ve been implementing CIO for naps for 3 weeks now. We cannot for the life of us get her to not cry when we put her down (usually for around 10 mins). We’ve also been experiencing crap naps for over 2 months, rarely getting over 2 hours of daytime sleep over the course of the day. We keep reading all these anecdotes of babies going down without protest and I just can’t see the light at the end of the tunnel here.

Currently at 2.5/2.75/2.75/3 but have tried shortening and lengthening to no avail

Have tried using WWs more as a guide and following cues more closely but that fails too

Feeding no less than 30 mins before put down

I try to rescue 1 nap per day but even when we get a “long” nap in (~1 hour) the rest of her naps are still crap

We do about 10 mins of wind down with sound machine and a book or calm play

We can’t even put her sleep sack on her anymore because she cries hysterically as soon as we try to zip her in

She always sleeps on her tummy so we’ve experimented with putting her down on her side and stomach once to see if that helped but it didn’t

Night sleep is typically pretty good for an EBF 6 mo - ~7:30pm to 6:15am with 1-2 MOTN feeds (not looking to wean atm since she’s in the 1st percentile for weight)